Launch vehicle payload chambers often carry communication satellites. Prior to launch, it is often necessary to check the operation of communication satellites located inside of payload chambers. Checking the operation of a communication satellite located inside of a payload chamber requires an antenna on the communication satellite to transmit data to a pick-up antenna located inside the payload chamber. The data is then re-transmitted from the pick-up antenna to a re-radiating antenna located outside the payload chamber and then again to a ground terminal. Alternatively, the antenna on the communication satellite may communicate to a pick-up antenna located outside of the payload chamber through an RF transparent window located in the fairing of the payload chamber. Reflections off the interior side of the fairing of the payload chamber can cause the pick-up antenna, located either inside or outside of the payload chamber, to experience severe signal modeing. This modal behavior if undamped, can cause time smearing of digital data as well as nulling of the power transfer between the communication satellite antenna and the pick-up antenna.
The traditional approach for diminishing modal behavior in a payload chamber is to position the pick-up antenna inside the payload chamber and to use a cantilevered mounting bracket to move the pick-up antenna around inside the payload chamber and generally towards the communication satellite antenna until a positive link margin exists between the pick-up antenna on the inside wall of the payload chamber and the communication satellite antenna signal. Typically, this bracket can be up to six feet in length. This approach suffers from at least three main problems. First, installation of the bracket and pick-up antenna can be complicated and time-consuming. Second, because the bracket is a movable part and because it generally extends toward the communication satellite, the use of the bracket creates an undesirable risk of hitting, and thus damaging, the communication satellite. Third, the use of the bracket adds unnecessary weight to the payload chamber and thus increases launch vehicle thrust requirements.
Therefore, there exists a need for an RF absorber system that addresses the above issues, is simple, lightweight, and reliable, and saves operational time.